1. Technical Field
Various embodiments relate to a semiconductor apparatus, and more particularly, to a resistance variable memory apparatus, a read circuit unit, and an operation method therefor.
2. Related Art
In a resistance variable memory device such as a phase change RAM (PRAM) or a resistance RAM (ReRAM), an information storage state is defined according to a resistance state of a data storage material.
During a write operation, the resistance variable memory device may apply a program current which can have a resistance state required by the data storage material. Furthermore, during a read operation, the resistance variable memory device may sense data stored in a memory cell by comparing a current value or voltage value corresponding to the amount of current flowing through the memory cell to a reference value.
The resistance of the data storage material forming the resistance variable memory device may be increased by various factors, and the increase in resistance of the data storage material may be referred to as a resistance drift.
The resistance drift determines a data retention time, and the data retention time serves as an important factor which determines the lifetime of the resistance variable memory device.